Juniper Greene lives in a walled city from which nature has been banished, following the outbreak of a deadly man-made disease many years earlier. While most people seem content to live in such a cage, she and her little brother Bear have always known about their resistance to the disease, and dream of escaping into the wild. To the one place humans have survived outside of cities. To where their mother is.

When scientists discover that the siblings provide the key to fighting the disease, the pair must flee for their lives. As they journey into the unknown, they soon learn that there’s cruelty in nature as well as beauty. Will they ever find the home they’re searching for?